U.S. Geological Survey, Customer Service Representative, 20100101, LANDFIRE.US_130VDEP: , http://landfire.cr.usgs.gov/viewer/, http://www.landfire.gov.
Summary
Broad-scale alterations of historical fire regimes and vegetation dynamics have occurred in many landscapes in the U.S. through the combined influence of land management practices, fire exclusion, ungulate herbivory, insect and disease outbreaks, climate change, and invasion of non-native plant species. The LANDFIRE Project produces maps of simulated historical fire regimes and vegetation conditions using the LANDSUM landscape succession and disturbance dynamics model. The LANDFIRE Project also produces maps of current vegetation and measurements of current vegetation departure from simulated historical reference conditions. These maps support fire and landscape management planning outlined in the goals of the National Fire Plan, Federal [...]
Summary
Broad-scale alterations of historical fire regimes and vegetation dynamics have occurred in many landscapes in the U.S. through the combined influence of land management practices, fire exclusion, ungulate herbivory, insect and disease outbreaks, climate change, and invasion of non-native plant species. The LANDFIRE Project produces maps of simulated historical fire regimes and vegetation conditions using the LANDSUM landscape succession and disturbance dynamics model. The LANDFIRE Project also produces maps of current vegetation and measurements of current vegetation departure from simulated historical reference conditions. These maps support fire and landscape management planning outlined in the goals of the National Fire Plan, Federal Wildland Fire Management Policy, and the Healthy Forests Restoration Act. Data Summary: The Vegetation Departure (VDEP) data layer categorizes departure between current vegetation conditions and reference vegetation conditions according to the methods outlined in the Interagency Fire Regime Condition Class Guidebook (Hann and others 2004). Technical Methods: "Summary units" for the departure computation were defined as a BioPhysical Setting (BpS) with identical reference condition values regardless of map zone. This is a change from previous versions of LANDFIRE. For example, speculate that a particular BpS is present in map zone 1, 2, 4, 5, 6 and 8. The reference conditions for this BpS are identical in map zones 1, 2, 4, 5 and 8 so those map zones become a "summary unit" for the departure computation (VDEP) in LF2012. Since reference conditions are unique for this BpS in map zone 6, it is a separate summary unit for calculating departure (VDEP) in LF2012. Within each biophysical setting in each summary unit, we compare the reference percentage of each succession class (SClass) to the current percentage, and the smaller of the two is summed to determine the similarity index for the BpS. This value is then subtracted from 100 to determine the departure value. Departure value is between 0 - 100, with 100 representing maximum departure. The LANDFIRE VDEP approach differs from that outlined in the Interagency Fire Regime Condition Class Guidebook (Hann and others 2004) as follows: LANDFIRE VDEP is based on departure of current vegetation conditions from reference vegetation conditions only, whereas the Guidebook approach includes departure of current fire regimes from those of the reference period. The reference conditions are derived from quantitative vegetation and disturbance dynamics models developed in VDDT/ST-Sim. The current conditions are derived from the corresponding version of the LANDFIRE Succession Class data layer; please refer to the product description page at landfire.gov for more information. The proportion of the landscape occupied by each SClass in each BpS unit in each summary unit is used to represent the current condition of that SClass in the VDEP calculation. The areas currently mapped to agriculture, urban, water, barren, or sparsely vegetated BpS units are not included in the VDEP calculation; thus, VDEP is based entirely on the remaining area of each BpS unit that is occupied by valid SClasses. Additional data layer values were included to represent Water (111), Snow / Ice (112), Urban (120), Barren (131), Sparsely Vegetated BpS (132), and Agriculture (180).
LANDFIRE data products are designed to facilitate national- and regional-level strategic planning and reporting of management activities. Data products are created at a 30-meter grid spatial resolution raster data set; however, the applicability of data products varies by location and specific use. Principal purposes of the data products include providing, 1) national-level, landscape-scale geospatial products to support fire and fuels management planning, and, 2) consistent fuels data to support fire planning, analysis, and budgeting to evaluate fire management alternatives. Users are advised to evaluate the data carefully for their applications.